Hello Mu4,
Welcome to the community!
Firstly, you should note that these forums are community-driven and not intended as a venue for customer services. We do not have access to customers' accounts nor would we know the details of your particular situation.
Unfortunately, I have not been able to verify that number actually belongs to Fido/Rogers. You might consider contacting Fido customer service to verify the details of your situation.
If the call was legitimate, the new number could be a part of the porting process. When purchasing a new plan, the line will be provided a phone number (temporary, if you intend on porting one in). You will only be able to get your current phone number once the porting process completes (see here). A new line cannot be created without a phone number and your phone number cannot port-over without an active line. There may not be any malintent in your line having a new number. It is a necessary part of the process.
Hope this helps 😀
Cheers
